1. Field of the Invention
The invention relates to magnetic-type information cards and to a method and apparatus for encoding and reading magnetic-type information cards. More particularly the invention relates to mag-stripe information cards which are capable of withstanding the abusive and rough treatment of everyday use, such as of students who use them in magnetic-flux-type readers to determine whether they are entitled to a meal under various meal plans which are encoded on the card together with the identification of the student.
The rough treatment for example which students give to identification and meal plan mag-stripe cards is really unbelievable until one has seen such cards after being used by a large number of students over long periods of use, such as several weeks or months and for two or three times per day. In many cases the cards are bent back and, if a rigid type card, are broken; and if flexible, they are often bent double and creased on the magnetic stripe. The flexible cards are often crumpled and creased. Moreover the users often do not carry the cards in their wallets but instead carry them in their pockets where they may come in contact with keys, coins and the like material which can physically affect the magnetic stripe if it is not protected by an adequate overlay.
While the above such treatment may be particularly prevalent among students, similar rough treatment also occurs with hospital cards, industry and commerce card use and other uses where the cards are used several times per day for months at a time.
An object of this invention is to provide a flexible resilient information card which can withstand treatment such as above described and which can be read after such treatment, including creasing on the magnetic stripe, by magnetic-type readers with a first rejection rate because of an error in reading of less than one percent of the cards.
Another object is to provide an information card having a protective layer of 2 mils (0.002 inch) or greater thickness over the magnetic layer and which provides the maximum amount of information in a small space and with the least number of tracks without reading error.
Another object is to provide improved methods and means for recording information on mag-stripe cards which have a coating of thickness of 2 mils (0.002 inch) or greater over the magnetic stripe and for thereafter reading said information.
A further object is to provide improved means and methods for reading flexible resilient mag-stripe cards having a flexible resilient over layer.
2. Prior Art
Flexible mag-stripe information cards are known to the art, for example see Engelhardt et al. U.S. Pat. No. 3,308,010, but so far as I know such cards are not in commercial use. Such cards have a layer over the magnetic oxide layer of approximately 0.5 mils (0.0005 inch). A flexible card with such a thin overlay will not give adequate protection against rubbing by keys and the like. Such cards, with the normal prior art magnetic transition spacing, when bent double and creased on the magnetic stripe and then flattened, will give erroneous readings.
So far as I know the mag-stripe cards in present commercial use are so rigid that they cannot be bent double and creased without breaking. Also they all have either no overlay or an extremely thin overlay of about 0.5 mils (0.0005 inch) or less. The standard mag-stripe card used by the American Bankers Association is relatively rigid and brittle in bending. It has the magnetic stripe on or very near the surface and is encoded at approximately 225 flux transitions per inch using one track.
The present trend for information cards appears to be in the direction of mag-stripe cards which are relatively rigid and which have as thin a layer as possible over the magnetic particle layer, since the thinner the overlay the better the resolution and the greater the information density.
The recently issued Kramer U.S. Pat. No. 3,811,977 shows an information card analogous to a punch card having magnetized spots that have a thick overlay of a thickness like that of applicant's invention but such a card is made of rigid vinyl and is not sufficiently flexible to be bent and creased without breaking. Further, the spacing of the magnetized spots, due to the Kramer system of simultaneous stationary encoding is not desirable or economical when a considerable amount of information is needed on a card.